One of the most popular series that Hot Wheels released was the 1998-1999 Long Haulers and the 2000-2003 Pavement Pounders .  These are sets with a Truck/Trailer combo and a Hot Wheels vehicle.   This series used popular castings including the ’57 Chevy, Scorchin’ Scooter, and the Dodge Viper.  These are now set up on hobbyDB as separate items (truck/trailer combo and the vehicle) and as sets.  This will allow you to add these to your collection whether you have them loose or in package.  In 2004, the series name changed to Truckin’ Transporters which is the next section that will have this feature soon.